Conventional power generating systems control output voltage to maintain the same at or near a phase voltage reference level. Overload protection is typically obtained by sensing the phase current and reducing the phase voltage reference level if the phase current exceeds its rated value. The overcurrent characteristic curve is implemented in a look-up table. Such a conventional approach has three disadvantages. Namely, the overcurrent characteristics do not precisely limit power since power is a function of the power factor which varies with load. Also, the slope in the overcurrent characteristic curve determines the gain of the closed loop. Retuning the overcurrent characteristic would require retuning a compensation block. Finally, the gain around zero voltage reference is highly nonlinear which may cause instability when operating at this point.
The present invention is intended to overcome one or more of the problems as set forth above.